Abstract P1-10-17: Axillary radiotherapy in selected patients with a preoperative diagnosis of lymph node involvement is a safe alternative to axillary lymph node dissection

Abstract

Abstract Introduction: Axillary lymph node dissection (ALND) is associated with significant morbidity. Randomised data [1,2] suggest that axillary radiotherapy (RT), or no further axillary treatment beyond sentinel node biopsy (SNB) may be safe. There are very few studies to guide the management of preoperatively diagnosed lymph node metastases either in the context of neoadjuvant chemotherapy (NACT) or direct to surgery. The current UK recommendation is for ALND. In 2015 our policy changed to RT for carefully selected patients after MDT discussion. These data look at axillary recurrence for those patients having axillary RT Methods: Data were retrospectively collected on patients with preoperatively diagnosed lymph node metastases between January 2016 and December 2020. Patients undergoing surgery with a curative intent were included. The decision to offer axillary RT was made in the MDT based on clinical and radiological findings and the burden of disease in the axillary sample. Axillary recurrence was defined as disease recurring in the axilla with no distant disease. Results: Date were collected on 132 patients. Demographics and tumour status are outlined in Table 1. 55% of patients had neoadjuvant chemotherapy with a 52% path CR in the axilla. Table 2 gives the results for the axillary RT group. During the same time period 25 patient had ALND. Of those 2 (8%) had isolated LN recurrence. 18 patients had axillary RT following positive SLN after NACT. There was a single patient with axillary recurrence in this group. Conclusion: In the absence of randomised data to guide practice, these data show that in selected patients axillary radiotherapy is safe after axillary node sampling. The decision should be based on axillary burden, tumour biology, MDT and patient discussion. We await with interest the results of the Alliance A011202 trial to guide practice in patients having NACT in N1 disease. [1] Donker M, van Tienhoven G, Straver ME, Meijnen P, van de Velde CJ, Mansel RE, Cataliotti L, Westenberg AH, Klinkenbijl JH, Orzalesi L, Bouma WH, van der Mijle HC, Nieuwenhuijzen GA, Veltkamp SC, Slaets L, Duez NJ, de Graaf PW, van Dalen T, Marinelli A, Rijna H, Snoj M, Bundred NJ, Merkus JW, Belkacemi Y, Petignat P, Schinagl DA, Coens C, Messina CG, Bogaerts J, Rutgers EJ. Radiotherapy or surgery of the axilla after a positive sentinel node in breast cancer (EORTC 10981-22023 AMAROS): a randomised, multicentre, open-label, phase 3 non-inferiority trial. Lancet Oncol. 2014 Nov;15(12):1303-10. doi: 10.1016/S1470-2045(14)70460-7. [2] Giuliano, A.E.; Ballman, K.; McCall, L.; Beitsch, P.; Whitworth, P.W.; Blumencranz, P.; Leitch, A.M.; Saha, S.; Morrow, M.; Hunt, K.K. Locoregional Recurrence After Sentinel Lymph Node Dissection With or Without Axillary Dissection in Patients With Sentinel Lymph Node Metastases: Long-term Follow-up From the American College of Surgeons Oncology Group (Alliance) ACOSOG Z0011 Randomized Trial. Ann. Surg. 2016, 264, 413–420 Table 1. Demographics and tumour status. Table 2. Patients having Axillary RT. Citation Format: Hamza A. Arabiyat, Iain Brown, Philip Drew, Rachel English, Mona Sulieman, Imran Abbas, Duncan Wheatley, Kali Potiszil, Alastair Thomson, Polly King. Axillary radiotherapy in selected patients with a preoperative diagnosis of lymph node involvement is a safe alternative to axillary lymph node dissection [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-10-17.